I decided to register an account with this forum in order to help fellow gamers figure out how to use UTStatsdb for offline play. While the code works flawlessly I have sadly found the documentation to be lacking. Not everyone is a boss at coding, not even at doing basic Windows stuff and, sincerely, why not dedicate thirty minutes to write a simple guide when you've literally done days of code.

So this is for people wanting to log and view stats for UT3 in offline play. I'm positive other Unreal Tournament games and their relevant online modes work in a similar fashion but can't provide info as I haven't tried anything online yet.

What I've done is including some much needed steps in the UTStatsdb Readme which is going to be posted below:

If done correctly you will find two new mutators in the Mutators screen, just when you are about to launch a game, in the same list with InstaGib and others. Select at least one of the UT3Stats mutators.

There are two versions of UT3Stats, one of which has El Muerte's LibHTTP5
compiled in. This version is designed to enable uploading log files to the
server and parsing the logs automatically. Currently this is still under
development and fails to function for most people. The best method for
transfering log files to your remote stats server is via FTP.

Add the following to your server startup script:
?Mutator=UT3Stats.UT3Stats

You will need to configure UT for generating logs and making them
available to UTStatsDB. Use UT3Stats, which is provided among these
extras.

When you have done all of the above, you need to go into the Admin page and set the logs' path. Try something easy like C:/Games/Unreal Tournament 3/Logs. And REMEMBER, THE BARS ARE THE ONES YOU TYPE WITH SHIFT + 7 (//// NOT \\\\).

If you want to parse team games (Team Deathmatch, Capture The Flag, etc.) you have to select the relevant option in the logs configuration page and set it to "true". It is one of the circular buttons you click.

You also need to write the log prefix. In UT3 it is Stats-7777 (check it,
I may be wrong).

You will need to review some option under Main Configuration too, to have bots counted as players, etc. For some reason UTStatsdb is currently ignoring me as a human player but lists me as a bot. It may have something to do with the fact I only played offline so far.

Once processed logs are moved from the path you gave to the UTStatsdb
folder, inside Logs.